Our aim is to use E. coli cell-free filtrates as an adjuvant for topical anthrax DNA vaccines. We have found that application to the bare skin of Escherichia (E.) coli vectors encoding DNA for the Bacillus anthracis (B. anthracis) protective antigen (PA), an non-toxic form of lethal factor (LF), was able to elicit humoral responses. We have further demonstrated that topical application of E. coli cell-free filtrates can enhance the immune responses against a co-administered prototype antigen. We hypothesize that E. coli components such as LPS, CpG, and proteins act synergistically to enhance the immunogenicity of co-administered antigens. In this study, we plan to determine whether an E. coli filtrate can serve as an adjuvant for topical anthrax vaccine applied directly to the skin. We will evaluate the effect of E. coli filtrates on skin Langerhans cells, yST cells, and other cell types. Finally, we will attempt to determine which components of the E. coli filtrate (LPS, CpG) have adjuvant capabilities. By capitalizing on the ability of non-pathogenic E. coli to serve as a strong adjuvant for topically applied vaccines, the filtrates and the potent immuno-initiating function of skin, vaccination against anthrax may be achieved in a simple, effective, economical, painless, and safe mode by topical application of B. anthracis antigens to the surface of the skin.